ORIGINAL STORY: So far 13 bodies and more than 150 pieces of debris have been recovered in the aftermath of Sunday's Russian military plane crash,
CNN reports, citing the Itar-Tass news agency.

The plane crashed into the Black Sea early Sunday morning shortly after taking off from Sochi with 92 people on board, including members of the Russian army choir.

On Monday, Kremlin spokesman Dimitri Peskov told reporters terrorism was not suspected as the cause of the crash.

Criminal investigation

Instead, Peskov said the plane likely crashed due to mechanical failure or pilot error.

The Russian Investigation Committee launched a criminal investigation to see if anyone violated the flight safety or preparation rules.

Since the crash, 3,500 people, 43 ships and 182 divers have been deployed to search for bodies and debris, according to
ABC News.

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Flowers lay in front of a photo of a well-known military choir lays flowers at the military choir's building in Moscow, Russia, Sunday, Dec. 25, 2016, after a plane carrying 64 members of the Alexandrov Ensemble, crashed into the Black Sea minutes after taking off from the resort city of Sochi. The Russian plane was headed for an air base in Syria with 92 people aboard, Russia's Defense Ministry said. (AP Photo/Pavel Golovkin)

Flowers and candles are placed at the well-known military choir's building in Moscow, Russia, Sunday, Dec. 25, 2016, after a plane carrying 64 members of the Alexandrov Ensemble, crashed into the Black Sea minutes after taking off from the resort city of Sochi. The Russian plane was headed for an air base in Syria with 92 people aboard, Russia's Defense Ministry said. (AP Photo/Pavel Golovkin)

A man places a candle at the well-known military choir's building in Moscow, Russia, Sunday, Dec. 25, 2016, after a plane carrying 64 members of the Alexandrov Ensemble, crashed into the Black Sea minutes after taking off from the resort city of Sochi. The Russian plane was headed for an air base in Syria with 92 people aboard, Russia's Defense Ministry said. (AP Photo/Pavel Golovkin)

Alexander, a former member of the Alexandrov Ensemble, a well-known military choir lays flowers at the military choir's building in Moscow, Russia, Sunday, Dec. 25, 2016, after a plane carrying 64 members of the Alexandrov Ensemble, crashed into the Black Sea minutes after taking off from the resort city of Sochi. The Russian plane was headed for an air base in Syria with 92 people aboard, Russia's Defense Ministry said. (AP Photo/Pavel Golovkin)

Russian President Vladimir Putin declared Monday a national day of mourning.

Human rights activist among dead

Searchers have been using data from radio location equipment to narrow their search and locate the crash site.

Russia's defense ministry said Monday that eight crew members, eight soldiers and more than 60 members of the Alexandrov Ensemble choir were among those feared dead. In addition, CNN reports that the famous Russian human rights activist, Liza Glinka, was also on board.

Wreckage a mile offshore

"Military personnel of the Southern Military district keep examining the shoreline to find and collect the bodies, debris of the plane and personal belongings of passengers," Russia's defense ministry told CNN.

All of the bodies and debris that were found as of Monday morning were flown to Moscow, where scientists will conduct DNA tests. CNN reports that divers found the Tupolev Tu-154 plane's fuselage approximately a mile offshore.